Radio systems have many transceivers for providing radio communications to and from vehicles for example military vehicles and the like. A RF Control Bus (RFCB) is a bidirectional Serializer/Deserializer (SerDes) serial link which transmits Clock and data between transceivers and the external RF hardware such as for example power amplifiers and filters. The RF hardware sends transmit data to an encoder where the data is encoded and the encoded data is send to the transceiver for transmission to other vehicles. Such transceivers can also receive data from other vehicles. Such data is send to RF hardware such as filters after decoding. This invention can be used in any communication link between any type of devices.
Conventional radio systems use low speed serial transceivers such as for example a Dual Integrated Core Engine Transceiver (DICE-T). DICE-T utilize 10NCJ program which runs at 500 Mbps and has 8b/10b encoding. With such transceivers, the data processing such as encoding and decoding are performed at 500 Mbps data rate. Also certain convention GMR transceiver use a custom RF control bus which is a serial bus operating at low frequencies for example 500 Mbps.
Programmable logic devices (PLDs) exist as a well-known type of Integrated Circuit (IC) that can be programmed by a user to perform specified logic functions. The PLDs can be of programmable logic arrays (PLAs) or Complex Programmable Logic Devices (CPLDs). One type of PLD, called a Field Programmable Gate Array (FPGA), is popular because of a superior combination of capacity, flexibility, time-to-market, and cost.
Modern radio systems utilize high speed serial FPGA transceivers such as for example Altera Cyclone IV. The high speed serial FPGA transceivers run at higher frequencies than what is required in the 10NCJ program. For example Altera Cyclone IV utilized in the 10NCJ program run at a minimum data rate of 600 Mbps with 8b/10b encoding. Conventional GMR transceivers utilized on the 10NCJ program are required to run at 500 Mbps with 8b/10b encoding.
To perform proper encoding and decoding of the RFCB data, a unique approach to the 8b/10b encoding must be implemented which runs the transceivers at 2 Gbps. The Cyclone IV device transceiver does provide hardware 8b/10b encoders and decoders but these cannot be utilized since the transceiver is actually running at 2 Gbps but the encoding must be performed as if the data was 500. Mbps. A need exists, therefore, for a way to emulating low frequency Clock Data Recovery Serial control bus operation using high frequency data.